As examples of a high-performance permanent magnet, rare-earth magnets such as a Sm—Co-based magnet and a Nd—Fe—B-based magnet are known. These magnets that are currently mass-produced contain a large amount of Fe or Co. Fe and Co contribute to an increase in saturation magnetization. A permanent magnet used in a drive motor of a vehicle such as a hybrid electric vehicle (HEV), an electric vehicle (EV), or a railway vehicle is required to have heat resistance. In a drive motor of a vehicle such as HEV, EV, or a railway vehicle, a permanent magnet that is a Nd—Fe—B-based magnet in which Dy replaces part of Nd to increase heat resistance is used, for instance. Since Dy is one of rare-earth elements, there is a demand for a permanent magnet not using Dy. A Sm—Co-based magnet is known as a magnet that has a system not using Dy yet exhibits excellent heat resistance, but has a drawback of being smaller in the maximum energy product (BH)max than a Nd—Fe—B-based magnet.
Factors determining a value of (BH)max of a permanent magnet include residual magnetization, a coercive force, and a squareness ratio. In order to increase the magnetization of a Sm—Co-based magnet, replacing part of Co by Fe and increasing the Fe concentration are effective. However, a Sm—Co-based magnet having a composition region high in the Fe concentration is likely to have a difficulty in having a high sintered body density and exhibiting an excellent squareness ratio. Under such circumstances, there is a demand for an art to achieve high residual magnetization and a high squareness ratio in a Sm—Co-based magnet having a high Fe concentration while keeping its coercive force sufficient.